The capture and detection of ionizing radiation in an efficient way, without significant loss or degradation of the image information, is of paramount significance in medical imaging.
Recent advances in medical detector technology make it possible for superior images to be produced by means of digital electronic techniques compared with classical film-screen techniques. In fact, considerable efforts are in progress to develop new methods of radiographic imaging that utilize recent advances in electronics and computer technology to improve diagnostic quality and to evolve new diagnositic modalities with reduced patient dose. These methods are generally known as digital radiography.
Specifically, digital radiography has many advantages over the conventional radiography such as expanded display of detector dynamic range, fast iamge acquisition and display, convenient storage, transmission and display of stored images without degradation, extended capabilities of data analysis and image processing and reduced patient dose.
Different detector technologies and beam geometries have been proposed for digital radiography, classified such as scintillator-photodiode, high-pressure gas filled detectors, scintillators-photomultiplier, kinestatic charge detector, proximity image intensifier/CCD, phosphor screen-photodiode and diode array.
Some of the disadvantages presently faced in the field relate to the relatively high initial cost of the digital radiographic systems, as well as to the limited detector resolution. The detector system should be ocnditioned by design criteria aimed at increasing spatial, temporatl resolution and contrast resolution, detective quantum efficiency (DQE) and the signal-to-noise ratio, while maintaining sufficient sampling rates. A careful design and development of the detecotr would be required to provide a beneficial impact on x-ray capture and their efficient conversion into charge carriers.